I'm assuming (and I may be completely wrong) that some kind of software monitors if the database of customer details is being downloaded. If a download is detected, an alert is issued. Does software like this exist? Or there other measure that guard against these data breaches?
There is some software that can detect an anomaly in the regular pattern of network usage, and possibly even cut the connection, but again, I'm not sure how effective they would be here.
In any case, considering they were using unsalted SHA-1 hashes of the passwords, which was well known to be a poor practice, you should probably assume they had very little protections.
b) There is software (intrusion detection systems/software, or IDS) that does that, but it is rarely present by default. The hows and whys of IDS can be difficult for non-security types to grok, and it can be costly in terms of time, equipment, and money, so it often not encountered.